This type of cylinder devices is conventionally known to be applied to, for example, a railroad vehicle to suppress vibrations in lateral direction relative to an advancing direction of a vehicle body by being interposed between the vehicle body and a truck.
Such a cylinder device is disclosed, for example, in Japanese Patent Application Laid-Open No. 2005-7944 or 2006-137294, and is constituted as a double-rod type, including, as shown in FIG. 6, a cylinder 100, a piston 101 slidably inserted into the cylinder 100, a rod 102 inserted into the cylinder 100 with a middle portion thereof being connected to the piston 101, and a hydraulic circuit 105 for selectively supplying pressure oil to one of two working chambers 103 and 104 partitioned by the piston 101 within the cylinder 100.
More specifically, the hydraulic circuit 105 includes a two-way discharge pump 107 normally and reversely rotated by a motor 106, a pair of flow passages 108 and 109 connecting the pump 107 to the working chambers 103 and 104 respectively, on-off valves 110 and 111 provided respectively in the middle of the flow passages 108 and 109, an accumulator 112 performing volumetric compensation in oil temperature change or the like, and a low-pressure priority shuttle valve 113 connected to the flow passages 108 and 109 in parallel to the pump 107 to connect the low-pressure side of the working chambers 103 and 104 to the accumulator 112.
Therefore, when the rod 102 in this cylinder device is driven, for example, to the left, the pump 107 is driven to supply the pressure oil to the flow passage 109, and the on-off valves 110 and 111 are opened. The pressure oil is then supplied to the right working chamber 104 to press the piston 101 to the left, whereby the rod 102 is driven to the left. The rod 102 can be driven to the right by reversely rotating the pump 107.